Multi-Density Sole Elements, and Systems and Methods for Manufacturing Same

ABSTRACT

The invention relates to sole elements for articles of footwear, and systems and methods for manufacturing same. One embodiment of the invention includes a method of manufacturing a sole element for an article of footwear including the steps of forming a sole element preform, inserting the sole element preform into a press mold cavity, and press-forming the sole element preform within the press mold cavity to form a unitary finished sole element comprising a first region having a first density and hardness and a second region having a second density and hardness different from the first density and hardness.

FIELD OF THE INVENTION

The present invention relates generally to the field of footwear, andmore particularly to articles of footwear having variable density orhardness sole elements, and related systems and methods for designingand manufacturing same.

BACKGROUND OF THE INVENTION

Many sports induce high levels of stress in the various joints of anathlete's feet and legs that may, over time, result in a risk of seriousfatigue and injury to one or more joints and/or muscles of the body(e.g., knee and/or cartilage injuries), which can reduce the performancelevel of the athlete and even make it impossible for them to compete.Example sports include, but are not limited to, track and field eventssuch as running, hurdling, etc., and sports requiring abrupt changes indirection such as soccer, rugby, tennis, squash, racquetball, badminton,football, baseball, field hockey, lacrosse, cricket, and basketball.

Providing appropriate levels of support and cushioning within a sole ofthe shoe can be highly beneficial in reducing the risk of injury due tooverstressing of the foot and/or leg of an athlete during such athleticactivity. As a result, shoes are often fitted with support elements tocontrol and reduce the effects of potentially damaging body movementsduring a gait cycle or cutting motion. For example, support elements areoften incorporated into footwear to assist in preventing unwelcomemovement of the ankle through over-pronation or over-supination.Pronation is a rotation or turning of the foot from a lateral side(i.e., the outer side) of the foot to a medial side (i.e., the innerside) of the foot. During a standard gait cycle the foot typicallycontacts the ground at first with the outer (i.e., lateral) part of theheel, after which the ankle rotates towards the medial side as weight isshifted to the midfoot and forefoot portions of the foot prior topushing-off. Supination is a corresponding turning of the ankle from themedial side to the lateral side of the foot. Over-pronation andover-supination can result in significant stress being placed on theankle and knee of the athlete. In general, support elements within ashoe to prevent over-pronation/supination involve relatively complicatedarrangements of material and support mechanisms that often addsignificant cost, complexity, and weight to the footwear.

While methods of manufacture to produce more simple and cost effectivesole units with stability functionality incorporated therein have beensuggested (see, for example, U.S. Pat. No. 7,464,428, the disclosure ofwhich is incorporated herein by reference in its entirety), there isstill a need for improved sole elements for providing controlled andtargeted support and cushioning for an article of footwear without theneed for complicated and expensive manufacturing methods and parts.

SUMMARY OF THE INVENTION

The present invention is directed towards customized footwear (and alsoapparel and/or sporting equipment) and elements thereof, and relatedsystems and methods for designing and manufacturing same, withcustomized elements adapted to provide targeted levels of support andcushioning for a broad range of athletes and athletic activities.

One aspect of the invention includes a method of manufacturing a soleelement for an article of footwear. The method includes the steps offorming a sole element preform, inserting the sole element preform intoa press mold cavity, and press-forming the sole element preform withinthe press mold cavity to form a unitary finished sole element. Theunitary finished sole element may include a first perimeter regioncomprising a first maximum density and/or hardness, a second perimeterregion comprising a second maximum density and/or hardness, a thirdperimeter region comprising a third maximum density and/or hardness, anda central region comprising a fourth maximum density and/or hardnessextending between at least a portion of the first perimeter region,second perimeter region, and third perimeter region.

In one embodiment, the first perimeter region includes at least aportion of a lateral side region of the sole element, the secondperimeter region includes at least a portion of a medial side region ofthe sole element, and the third perimeter region includes at least aportion of a lateral heel region of the sole element. The third maximumdensity and/or hardness may be less than at least one of the firstmaximum density and/or hardness or the second maximum density and/orhardness. The sole element preform may include, or consist essentiallyof, a polymeric material such as, but not limited to, ethylene vinylacetate.

Forming the sole element preform may include foaming unfoamed polymericmaterial in a first (or preform) mold cavity. The press mold cavity mayhave a volume smaller than that of the first mold cavity, with the stepof inserting the sole element preform into the press mold requiringover-stuffing the sole element preform into the press form cavity.

In one embodiment the unfoamed polymer material further includes atleast one coloring material. Upon foaming the unfoamed polymericmaterial this coloring material may be unevenly distributed throughoutthe sole element preform and can, in certain embodiments, provide avisual indication representative of a differentiation in density and/orhardness in different regions of the finished sole element.

In one embodiment the first maximum density and/or hardness is less thanthe second maximum density and/or hardness, the third maximum densityand/or hardness is less than both the first maximum density and/orhardness and the second maximum density and/or hardness, and the fourthmaximum density and/or hardness is less than at least one of the firstmaximum density and/or hardness and the second maximum density and/orhardness. At least one of the first perimeter region, second perimeterregion, third perimeter region, and/or central region may have a densityand/or hardness that varies in at least one direction. The finished soleelement may be adapted to form at least a heel portion of a midsole ofan article of footwear.

Another aspect of the invention includes a sole element for an articleof footwear. The sole element includes a first perimeter region having afirst maximum density and/or hardness, a second perimeter region havinga second maximum density and/or hardness, a third perimeter regionhaving a third maximum density and/or hardness, and a central regionhaving a fourth maximum density and/or hardness and extending between atleast a portion of the first perimeter region, second perimeter region,and third perimeter region. Each of the first perimeter region, secondperimeter region, third perimeter region, and central region may beformed as a unitary construction (i.e., as a single integrated part formas one from a single material, or single group of materials).

In one embodiment the first perimeter region includes at least a portionof a lateral side region of the sole element, the second perimeterregion includes at least a portion of a medial side region of the soleelement, and the third perimeter region includes at least a portion of alateral heel region of the sole element. The third maximum densityand/or hardness may be less than at least one of the first maximumdensity and/or hardness or the second maximum density and/or hardness.The unitary construction may be formed from a polymeric material suchas, but not limited to, ethylene vinyl acetate. In one embodiment thepolymeric material includes at least one coloring material which mayprovide a visual indication representative of a differentiation indensity and/or hardness in different regions of the sole element.

In one embodiment the first maximum density and/or hardness is less thanthe second maximum density and/or hardness, the third maximum densityand/or hardness is less than both the first maximum density and/orhardness and the second maximum density and/or hardness, and the fourthmaximum density and/or hardness is less than at least one of the firstmaximum density and/or hardness and the second maximum density and/orhardness. At least one of the first perimeter region, second perimeterregion, third perimeter region, and/or central region may include adensity and/or hardness that varies in at least one direction. The soleelement may be adapted to form at least a heel portion of a midsole ofan article of footwear.

Another aspect of the invention includes a sole element for an articleof footwear, the sole element including a first sole component and asecond sole component. The first sole component may include, or consistessentially of, a first material, the first sole component having anupper surface and a lower surface, the upper surface of the first soleelement forming at least a first portion of an upper surface of the soleelement. The second sole component may include, or consist essentiallyof, a second material, the second sole component having an upper surfaceand a lower surface, and at least a first portion of the upper surfaceof the second component adapted to mate to at least a portion of thelower surface of the first sole component. The second component mayinclude a first region having a first maximum density and/or hardness,and a second region having a second maximum density and/or hardnessdifferent from the first maximum density and/or hardness.

In one embodiment the first region of the second sole component includesat least one lateral extension extending upwards around at least aportion of a lateral side of the first sole component and having anupper surface adapted to extend to a same height as the upper surface ofthe first sole element to form a second portion of an upper surface ofthe sole element. The second region may include at least one medialextension extending upwards around at least a portion of medial side ofthe first sole component and having an upper surface adapted to extendto a same height as the upper surface of the first sole element to forma second portion of an upper surface of the sole element. In oneembodiment the second sole component further comprises a heel regioncomprising a third maximum density and/or hardness different from atleast one of the first maximum density and/or hardness and the seconddensity and/or hardness.

These and other objects, along with advantages and features of thepresent invention herein disclosed, will become more apparent throughreference to the following description, the accompanying drawings, andthe claims. Furthermore, it is to be understood that the features of thevarious embodiments described herein are not mutually exclusive and canexist in various combinations and permutations.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention. In the followingdescription, various embodiments of the present invention are describedwith reference to the following drawings, in which:

FIG. 1A is a schematic view of a preform mold cavity for forming a soleelement preform, in accordance with one embodiment of the invention;

FIG. 1B is a schematic view of a sole element preform being formed inthe preform mold cavity of FIG. 1A;

FIG. 1C is a sole element preform as formed by the preform mold cavityof FIG. 1A;

FIG. 1D is a schematic view of the sole element preform of FIG. 1C beinginserted into a press mold cavity, in accordance with one embodiment ofthe invention;

FIG. 1E is a schematic view of the sole element preform after insertioninto the press mold cavity of FIG. 1D;

FIG. 1F is a schematic view of a sole element being press formed in thepress mold cavity of FIG. 1D;

FIG. 1G is a schematic view of the finished sole element of FIG. 1F;

FIG. 2A is a top view of a sole element for a heel and midfoot region ofa shoe sole, in accordance with one embodiment of the invention;

FIG. 2B is a sectional side view of the sole element of FIG. 2A throughSection C-C;

FIG. 2C is a sectional end view of the sole element of FIG. 2A throughSection A-A;

FIG. 2D is a bottom view of the sole element of FIG. 2A;

FIG. 3 is a schematic end view of a sole element for a shoe before andafter press molding, in accordance with one embodiment of the invention;

FIG. 4A is a schematic end view of a sole element for a shoe having acoloring element distributed therethrough before press molding, inaccordance with one embodiment of the invention;

FIG. 4B is a schematic side view of the sole element of FIG. 4A afterpress molding;

FIG. 5 is a top view of a sole element for an article of footwear, inaccordance with one embodiment of the invention;

FIG. 6A is a top view of another sole element for an article offootwear, in accordance with one embodiment of the invention;

FIG. 6B is a medial side view of the sole element of FIG. 6A before andafter press molding;

FIG. 6C is a lateral side view of the sole element of FIG. 6A before andafter press molding;

FIG. 7A is a top view of a midsole for an article of footwearincorporating a multi-density midsole element, in accordance with oneembodiment of the invention;

FIG. 7B is a sectional side view of the sole element of FIG. 7A throughSection D-D; and

FIG. 8 is a side view of a shoe incorporating the midsole of FIGS. 7Aand 7B, in accordance with one embodiment of the invention.

DETAILED DESCRIPTION

The invention described herein relates to systems and methods forforming polymeric foamed articles having regions of differing physicalproperties (e.g., hardness and/or density) for use, for example, infootwear. The systems and methods described herein can be used toproduce components such as, but not limited to, soles, or componentstherefor, for footwear. More particularly, the systems and methodsdescribed herein may be used to produce multi-density and/or hardnessfoamed parts that may form an insole, midsole, and/or outsole of a shoe,or form a sole element for integration into an insole, midsole, and/oroutsole of the shoe (e.g., through bonding to, and/or mechanicalattachment to, another midsole element).

Differing physical properties of interest for different regions withinthe component include material density and material hardness. Materialdensity, i.e., the mass of the material per unit volume, provides anindication of how dense the material is, with denser materials generallyproviding more support and less flexibility and cushioning, while lessdense materials provide less resistance and therefore a greater level ofcushioning and flexibility. Hardness, and more specifically indentationhardness (i.e., a measure of the resistance of a sample to materialdeformation due to a constant compression load from a sharp object)provides an indication of the resistance to deformation of a material,with a higher hardness material providing more support and lessflexibility and cushioning, while lower hardness materials provide lessresistance and therefore a greater level of cushioning and flexibility.The methods and systems described herein will provide for solecomponents having multi-hardness and multi-density regions, with thehigher hardness regions corresponding to the higher density regions.

In various embodiments the methods and systems described herein can beused to produce multi-density/hardness parts for use in any number ofproducts. For example, such parts may form the sole, or a portion of asole, of an article of footwear and/or form at least a portion of anupper of an article of footwear. The multi-density/hardness parts canalso be integrated into garments for an upper and/or lower body of awearer, with the polymeric material being useful, for example, inproviding protective coverings and padding that is integrated into thegarment. For example, in some embodiments the multi-density/hardnessparts can be arranged so as to provide foamed protective elements forgarments or sporting accessories. The multi-density/hardness parts canalso be used in products such as, but not limited to, protective sportsaccessories (e.g., elbow pads, shin pads, head protectors, etc.),suitcases and other carrying bags, or the like.

One embodiment of the invention relates to a method of manufacturing amulti-density, multi-hardness, sole element (e.g., a multi-density“blocker” element) for incorporation into a midsole of an article offootwear. The method includes the steps of forming a sole elementpreform, inserting the sole element preform into a press mold cavity,and press-forming the sole element preform within the press mold cavityto form a finished sole element having a unitary structure includingmultiple regions of differing density and hardness.

The sole element preform may be manufactured from any appropriatetechnique and, for example, may be manufactured from molding methodssuch as, but not limited to, expansion molding, die-cutting, sculptingof foamed material, and/or compression molding. For example, the soleelement preform may be manufactured by providing a preform moldincluding at least one cavity, inserting unfoamed polymeric materialinto the cavity to partially fill the cavity with unfoamed polymericmaterial, and sealing the mold. The unfoamed polymeric material may thenbe foamed by the preform mold to form a preform element having anyrequired shape, size, and material properties (e.g., density) dependingupon the shape and volume of the preform mold cavity, the volume ofunfoamed polymeric material inserted into the cavity, and/or theproperties of the polymeric material being foamed.

The polymeric material may include, or consist essentially of, polymers,elastomers, and/or thermoplastics. For example, the polymeric materialmay be ethylene vinyl acetate (EVA), EVA copolymers, polyethylene (PE),chlorinated polyethylene (CPE), polyurethane (PU), thermoplasticpolyurethane (TPU), DuPont™ Surlyn®, blown rubber, or thermoplasticrubber (TPR). In one example embodiment the polymeric material is aground-contact EVA (i.e., an EVA formulated specifically to provideappropriate performance, wear, and durability characteristics to allowit to be used as the ground-contacting surface of a shoe sole).

In various embodiments a blowing agent may be introduced into theunfoamed polymeric material prior to foaming so as to provide a means offoaming the polymeric material. The blowing agent may be introduced intothe unfoamed polymeric material mixture with any appropriate blowingagent level. The blowing agent may include, or consist essentially of,any appropriate type of physical or chemical blowing agent known tothose of ordinary skill in the art such as, but not limited to,nitrogen, carbon dioxide, hydrocarbons (e.g., propane),chlorofluorocarbons, noble gases and/or mixtures thereof. In one exampleembodiment, the blowing agent comprises, or consists essentially of,nitrogen. The blowing agent may be supplied in any flowable physicalstate such as a gas, a liquid, or a supercritical fluid (SCF).Alternatively, the blowing agent may be supplied in the form of apelletized solid. According to one embodiment, a blowing agent sourceprovides a blowing agent (e.g., nitrogen) that is in a supercriticalfluid state upon injection into an extruder for extruding material intoa preform mold. In one embodiment a chemical blowing agent (e.g.,azodicarbonamide or modified-azodicarbonamide) in liquid form can bemixed with the unfoamed polymeric material and thereafter activated byheating to a temperature at or above its activation temperature.

The blowing agent may be dissolved, or otherwise mixed, into theunfoamed polymeric material such that it remains in a stable conditionuntil a specific condition is met, at which time it activates, comes outof solution, decomposes, gasifies, or otherwise initiates foaming tonucleate a plurality of microcell sites and thereby foam the unfoamedpolymeric material. For example, the blowing agent may be selected toactivate/come out of solution and foam the unfoamed polymeric materialwhen a set temperature is reached and/or when a set pressure is reached.

In one embodiment the unfoamed polymeric material with the blowing agentdissolved therein can be held at an elevated pressure, with the blowingagent activating when the pressure under which the unfoamed polymericmaterial is held is dropped (e.g., by expanding or opening (“cracking”)a mold cavity in which the unfoamed polymeric material is held). Forexample, the unfoamed polymeric material with the blowing agent mixedtherein (e.g., a supercritical fluid blowing agent) can be held at anelevated temperature and pressure within an upstream mixing andinjection system and in one or more injection channels connecting themixing and injection system with the mold cavity (or cavities), withfoaming automatically initiating as or shortly after the material exitsthe injection channel(s) and enters the mold cavity (or cavities).

Alternatively, unfoamed polymeric material with an embedded blowingagent is inserted into the preform mold cavity (for example in liquidform or in solid pellet form). The mold cavity is thereafter closed andheated to a temperature and/or pressure sufficient to activate theblowing agent, after which the unfoamed material can be foamed (e.g., by“cracking” the mold or by retracting a retractable wall in the mold). Inalternative embodiments any appropriate technique for forming a foamedpreform from unfoamed polymeric material may be utilized.

Once the foamed polymeric material preform has been created, the preformcan be inserted into a press-mold cavity to undergo press-form moldingto create the finished part. The structure and action of the press-moldcan be carefully selected to provide a greater degree of compression tocertain regions of the preform, and a lesser degree of compression toother regions of the preform, to produce a finished part havingdifferent densities in different regions. The press-form mold mayinclude one or more wall that presses down into the press-form moldcavity to reduce the volume within the cavity and compress the foamedpolymeric material preform located therein. The walls may be actuated tocompress the preform through any appropriate mechanical, pneumatic,hydraulic, electromagnetic, and/or other appropriate mechanism.

An example method of manufacturing a multi-density part is shown inFIGS. 1A through 1G. In this embodiment, a preform mold 100 is providedwith a first mold portion 105 forming a mold cavity 110, and a secondmold portion 115 for covering the cavity 110 to seal (or partially seal)the cavity 110 from the surrounding atmosphere. The second mold portion115 can be detachable from the first mold portion 105 or be pivotably,or otherwise movably, attached to the first mold portion 105. The secondmold portion 115 may be clamped, screwed, or otherwise detachably heldto the first mold portion 105 through any appropriate mechanical,pneumatic, hydraulic, and/or electromagnetic clamping system to ensurethat an appropriate seal within the cavity 110 is maintained during themolding process. In an alternative embodiment the mold 100 may haveadditional and/or differently shaped mold portions that can matetogether in any appropriate manner and/or be oriented in any appropriatemanner.

The cavity 110 is adapted to receive a volume of unfoamed polymericmaterial 120 (e.g., a volume of unfoamed EVA), as shown in FIG. 1B. Theunfoamed polymeric material 120 may be inserted into the cavity 110 insolid or liquid form. For example, the unfoamed polymeric material 120may be injected into the cavity 110 in liquid form through one or moreinjection ports 125. Alternatively, the unfoamed polymeric material 120may be inserted into the cavity 110 as a plurality of small pellets ofunfoamed material (with, for example, a blowing agent encapsulatedtherein) that are thereafter heated and melted into a liquid within thecavity 110 in order to activate the blowing agent and foam the unfoamedpolymeric material 120. Pellets of unfoamed polymeric material 120 maybe inserted into the cavity 110 by hand, or be held in a hopper andmanually or automatically released from the hopper into the cavity 110prior to foaming.

Once the unfoamed polymeric material 120 has been inserted into the moldcavity 110 the mold 100 can induce foaming of the polymeric material,through any appropriate foaming method (e.g., through expansion or crackmolding), to produce a foamed polymeric preform 130. The preform canthen be press-molded to produce a finished multi-density part. Theperform 130 may be asymmetrically formed, as shown in FIGS. 1B and 1Cwith a first extension 135, a second extension 140, and a base portion145. The first extension 135 extends further from the base portion 145than second extension 140, and therefore contains a larger volume ofmaterial than second extension 140. In various embodiments the perform130 may be of any size and shape and may include and number and/or shapeof extensions, protrusions, cavities, and or other appropriate shapingelements, depending upon the specific finished part being formed and thespecific density distribution required of the finished part.

The resulting foamed preform 130 can then be inserted into a second mold150 (i.e., a press-form mold) for press-forming into a finished part.The press-form mold 150 may include a first mold portion 155 forming apress-form mold cavity 160, and a second mold portion 165 for coveringthe cavity 160 to seal (or partially seal) the cavity 160 from thesurrounding atmosphere. In one embodiment the second mold 150 may form asealed, or substantially sealed, press-form mold cavity 160. In analternative embodiment the second mold 150 forms a press-form moldcavity 160 that is vented to the surrounding atmosphere through one ormore venting channels, or through one or more spaces or cracks betweendifferent mold components. In various embodiments the second mold 150may be thermally controlled (e.g., heated and/or cooled as required) toassist in the pressing and setting of the finished part 180.

In one embodiment, as shown in FIG. 1D, the preform 130 can have atleast one dimension (e.g., a width and/or height) larger than that ofthe press-form mold cavity 160 into which it is placed. As a result, thepreform 130 must be forced (i.e., “over-stuffed”) into the cavity 160such that the preform 130 is held in a compressed state within thecavity 160 prior to press-forming. This over-stuffing may be beneficialin controlling and supporting the creation of localized density changesafter compressing the foamed material into a finished part 180. In analternative embodiment the preform 130 may be shaped and sized to fitsubstantially exactly into the press-form mold cavity 160 without theneed for over-stuffing, or may, in one embodiment have at least onedimension smaller than that of the press-form mold cavity 160 (so thatthe preform 130 fits within the cavity 160 with a space between thepreform 130 and at least one wall of the cavity 160).

Once the preform 130 has been placed within the cavity 160 the mold 150is closed, as shown in FIGS. 1E and 1F, and the preform is compressed toform a finished part 180. The mold 150 may be closed by forcing thefirst mold portion 155 into contact with the second mold portion 165through any appropriate mechanical, pneumatic, hydraulic, and/orelectromagnetic mechanism.

In one embodiment the first mold portion 155 and the second mold portion165 are shaped and sized to form a press-form mold cavity 160 having adifferent shape from that of the preform mold cavity 110, as shown inFIG. 1F. As a result, upon closing the press-form mold 150 differentregions of the preform 130 undergo different levels of compressiondepending upon the difference in volume between that portion of thepreform 130 and the region of the press-form mold cavity 160 into whichit is placed. For example, in the embodiment shown in FIGS. 1E and 1Fthe press-form mold cavity 160 is symmetrically shaped with a firstextended cavity portion 170 (into which the longer first extension 135of the preform 130 is placed) having a substantially identical size andshape to a second extended cavity portion 175 (into which the shortersecond extension 140 of the preform 130 is located). As a result, uponclosing the mold 150 the first extension 135 will undergo a greaterlevel of compression than the second extension 140, thereby forming afinished part 180 having a first extension 135 having a greater densityand hardness than that of the second extension 140. The base portion 145is, in the embodiment of FIGS. 1E and 1F, compressed by an amountgreater than that of the second extension 140 but less than that of thefirst extension 135, thereby forming a base region having anintermediate density and hardness between that of the two extensions.

In various embodiments the press-form mold cavity 160 can be configuredto apply any distribution of compression to any appropriate region ofthe preform 130, depending upon the specific geometries of the preform130 and press-form mold cavity 160 and the specific density requirementsof the finished part. In an alternative embodiment the press-form moldcavity 160 can be configured to generate the same level of compressionover the entire preform 130, thereby forming a finished part having aneven density distribution.

In one embodiment the polymeric material 120 includes one or morecoloring elements that are unevenly (i.e., non-uniformly distributed,for example, as a web-like or marbled structure or as a distribution ofdiscrete spots or lines) distributed within the unfoamed polymericmaterial 120. This may be achieved, for example, by coating one or morepellets of unfoamed polymeric material 120 with a colored dye, pigment,or paint such that the interior or the pellets of unfoamed polymericmaterial 120 have a first color while the outer surface of the pelletshave a second color. Once this painted/coated polymeric material 120 isfoamed the coloring material is non-uniformly distributed throughout thefoamed perform 130 (i.e., both visible at the surface of the perform 130and distributed throughout the interior of the perform 130).Alternatively, a non-uniform distribution of colored material (e.g.,dye, paint, etc.) may be produced by mixing pellets of colored materialwithin the unfoamed polymeric material 120 such that the colored pelletsfoam with the polymeric material 120 and unevenly distribute throughoutthe resulting foamed preform.

When the preform 130 is compressed during press-forming, the coloringelements distributed throughout the preform 130 will also be compressed,with more densely packed regions of the finished part 180 having moredensely packed coloring elements. As a result, the coloring elements canprovide an indication of the level of compression (and therefor thedensity) of the various regions of the finished part 180. A visualindication of the variation in the density distribution of the finishedpart 180 is shown in FIGS. 1F and 1G, with the greater coloring (i.e.,the higher density of coloring element) within the first extension 135indicating a higher density of the foamed material in that portion, andwith the lesser coloring (i.e. the lower density of coloring element)within the second extension 140 indicating a lower density of the foamedmaterial in that portion. The intermediate coloring within the baseportion 145 indicates an intermediate density distribution within thatregion.

Use of coloring elements to provide an indication of the density of thefinished part 180 may be beneficial for a number of reasons. Forexample, the visual indication of the density distribution provides aquick and simple confirmation that the finished part 180 was formedcorrectly and does include the required density profile. The visualindication of density distribution produced by the coloring element(s)can also provide a clear differentiation between similarly shaped partshaving different density profiles (e.g., between two identically shapedmidsole components, one with the higher density region located in alateral side—a laterally posted insert—and one with the higher densityregion in the medial side—a medially posted insert). This may behelpful, for example, when assembling one of a selection of midsolecomponents into a specific shoe for a specific purpose. In addition, asthe coloring element is distributed throughout the finished part 180(rather than merely coated onto an outer surface of the finished part)the density distribution will still be visible even if the part is cut,shaved, or otherwise post-processed. The coloring elements may alsoproduce a unique and appealing visual aspect to a product incorporatingthe finished part 180.

One embodiment of the invention includes a sole component for an articleof footwear (such as, but not limited to, an athletic shoe, a walkingshoe, or an orthopedic shoe) formed using the methods described herein.The sole component may, for example, form a midsole of a shoe, or aportion thereof. In one embodiment the sole component may be shaped andconfigured to form at least a portion of a heel, a midfoot, and/or aforefoot portion of a midsole, and/or may be configured to extend overany appropriate portion of a medial lateral, and/or central region ofthe midsole. An example midsole component 200 for a shoe midsole isshown in FIGS. 2A through 2D.

The midsole component 200 includes a medial side portion 205, a lateralside portion 210, a heel portion 215, and a central portion 220 and isadapted to provide cushioning and support for a wearer in a shoe heelregion 225 and at least part of a midfoot region 230. The medial sideportion 205 and lateral side portion 210 form extensions that extendupwards from the central base portion 220 to provide perimeter supportto the foot of a wearer along the medial and lateral sides of the foot.In one embodiment the heel portion 215 may also extend upwards from thecentral/base portion 220 to provide perimeter support to a heel of awearer. This perimeter support may be beneficial, for example, incontrolling pronation or supination in a wearer and/or providingcontrolled support for various regions of the foot of the wearer (e.g.,a heel, an arch, and/or a plantar fascia).

The midsole component 200 includes a top surface 235 that is shaped andconfigured to mate with a second midsole component (e.g., a cushioningelement) placed above the midsole component 200 in the full assembledsole. In an alternative embodiment the top surface 235 of the midsolecomponent 200 may be shaped to directly provide an upper surface of thefinished sole without the need for one or more additional cushioningelements there-above. The midsole component 200 also includes a bottomsurface 240 that may provide a ground contacting surface for the shoeand/or that may engage with a separate outsole that is positioned belowthe midsole to provide a ground contacting surface for the shoe. In oneembodiment the bottom surface 240 includes one or more indentations orcavities 245 for mating with one or more outsole elements. In oneembodiment a bottom surface 240 and/or top surface of the midsolecomponent 200 may include flexibility grooves or other indentations orsiping.

Variations in density within the midsole component 200 can be created byforming a preform having a uniform density and thereafter selectivelypress-forming the preform to produce a finished part having differentdensities in different locations. An example cross-sectional contour ofa midsole component preform 250 and finished part 255 is shown in FIG.3. In this embodiment a medial side portion 260 is compressed by a firstamount (as indicated by the arrows 270) while a lateral side portion 265is compressed by a second, lesser, amount (as indicated by the arrows275). A central portion 280 is compressed by a still lesser amount (asindicated by the arrow 285). As shown, the preform 250 in the medialside portion 260 is shaped such that the medial side portion 260undergoes compression from multiple angles (including from below), whilethe lateral side portion 265 undergoes compression from only the top andside and the central portion 280 is compressed only in a verticaldirection. In an alternative embodiment the shape and size of thevarious portions of the preform 250 and finished part 255 may be of anyappropriate size and shape, depending upon the degree of compressionrequired in each portion to produce finished parts 255 having anydesired density distribution.

In certain embodiments one or more regions of the midsole component 200may be compressed by a range of values within that region, therebyproviding a varying density distribution within that region. Forexample, as shown in FIG. 3 the central portion 280 undergoes a greaterdegree of compression on its medial side than on its lateral side,thereby producing a variation in density across the width of the centralportion 280. In an alternative embodiment one or more regions can beconfigured to have a relatively, or exactly, constant density throughoutthat region.

As described above, coloring elements may be distributed throughout thepreform in order to produce a visual indication of the densitydistribution of the finished part after press-forming. An examplemidsole component preform 250 having colored material 290 unevenlydistributed therethrough is shown in FIG. 4A, with the resultingvariation in colored material 290 distribution in the finished part 255(i.e., after press-forming) shown in FIG. 4B. As shown, the highestdensity portion (the medial side portion 260) has a more densedistribution of colored material 290, and therefor appears more colored,than the lower density lateral side portion 265 or the lowest densitycentral portion 280. In various embodiments the coloring material 290,or materials, may be selected to provide any appropriate bold or subtlecontrast between the polymeric foamed material providing the structureof the part and the coloring material used to provide the visualindication of the density distribution.

An example midsole component 300 having a plurality of regions ofdiffering density can be seen in FIG. 5. In this embodiment, the midsolecomponent includes a raised perimeter portion 305 surrounding a centralbase region 310. The raised perimeter portion 305 includes a medial sideregion 315 (which extends from the leading edge 320 of the midsolecomponent 300 in a midfoot portion of the sole to the rear 325 of themidsole component 300 at the heel of the sole. A lateral heel portion330 extends from the rear 325 of the midsole component 300 around to alateral side portion 335, which extends along the lateral side of themidsole component 300 from the lateral heel portion 330 to the leadingedge 320 of the midsole component 300. In the embodiment of FIG. 5 themedial side region 315 extends further forward (towards a forefoot) thanthe lateral side portion 335. In alternative embodiments the medial sideregion 315 and lateral side portion 335 may extend the same distance, orthe lateral side portion 335 may extend further forward. In variousembodiments the leading edge 320 of the midsole component 300 may bepositioned at any distance along the length of the shoe and, forexample, may be located within the heel, between the midfoot and heel,within the midfoot, between the midfoot and forefoot, or within theforefoot. In one embodiment the midsole component 300 may extend thefull length of the shoe. In another embodiment the midsole component 300may be located within any portion of the heel, midfoot, and/or forefootof the shoe, and may cover any appropriate portion of the medial,lateral, and central portions of the shoe within those regions.

In the embodiment of FIG. 5 each of the perimeter regions (i.e., themedial side region 315, the lateral heel portion 330, and the lateralside portion 335) may have a different maximum density, with the densityeither constant or varying within each of these regions. In addition,the central base region 310 may have a maximum density equal to, orsubstantially equal to, a density of one of the perimeter regions, orhave a different maximum density from each of the perimeter regions.Again, the density of the central base region 310 may be constant acrossits full extent or vary across its area.

In one embodiment the maximum density within the medial side region 315,is greater than the maximum density within any other region of themidsole component 300. This may be beneficial, for example, in providingsupport for the medial side of a wearer's foot to control pronation. Inone embodiment the maximum density within the lateral heel portion 330may be lower than that of the other perimeter regions. This may bebeneficial, for example, in providing a more flexible cushioning for thefoot of the wearer during initial footstrike within a gait cycle (wherethe lateral heel of the foot is often the first contact point betweenfoot and ground during a running or walking motion.

In an alternative embodiment the perimeter portion 305 of the midsolecomponent 300 may be divided into any number of perimeter sections, withdiffering density profiles within each section, depending upon thespecific performance characteristics of the midsole component 300required for a particular shoe. For example, the perimeter portion 305may be configured as a single section having one set density, or asingle section having a smoothly varying density profile withinlocalized maximum and minimum densities in targeted areas. Alternativelythe perimeter section 305 can include any number of discrete sectionswith stepped or smoothly transitioning densities between each section.For example, the perimeter section 305 may be configured to include oneor more medial side portion, one or more lateral side portion, and/orone or more heel portion (e.g., one or more medial heel portion and oneor more lateral heel portion). The transitions between these regions maybe located at any appropriate positions along the perimeter 305.

Similarly, the central base portion 310 may be configured as a singlesection having one set density, or a single section having a smoothlyvarying density profile within localized maximum and minimum densitiesin targeted areas. Alternatively the central base portion 310 maycomprise any number of discrete sections with stepped or smoothlytransitioning densities between each section.

An example hardness distribution for a midsole component 300 is shown inFIGS. 6A to 6C, with regions or high hardness corresponding to regionsof higher density. FIG. 6A shows a plan view of the midsole component300 with an indication of the hardness of the material in variousregions of the midsole component 300 highlighted in Asker-C hardnessunits. Side views of the medial side and lateral side the midsolecomponent 300 are shown in FIGS. 6B and 6C respectively, with the shapeof the preform 350 used in the formation of the variabledensity/hardness distribution of the finished part 300 indicated. Asshown, the midsole component 300 has a medial side region 315 with ahardness and density that varies smoothly across its length, with afirst local maximum 355 in a midfoot region (to support an arch of awearer) and a second local maximum 360 in a medial heel region. Themedial side region 315 extends around the medial heel portion to therear 325 (i.e., the back of the heel) of the midsole component 300 andtransitions (or blends) into the lateral heel portion 330, which has alower density and hardness than the medial side region 315 with alocalized minimum 365. The lateral heel portion 330 then blends into thelateral side portion 335, which has a larger maximum density andhardness than the lateral heel portion 330 at a localized maximum 370.The maximum density and hardness within the lateral side portion 335 isless than that of the medial side region 315.

As shown, the central base region 310 has a localized maximum densityand hardness 375 within the midfoot region (i.e., near the leading edge320 and positioned below an arch of a wearer), with the heel region ofthe central base region 310 having a lower density and hardness (toprovide more cushioning under the heel of the wearer).

In various embodiments the maximum and minimum hardness's and densitiesof the various regions of the midsole component 300 may be larger orsmaller than that shown (depending upon the polymeric material used andthe level of compression applied during the press-forming process) andthe hardness, for example, may range between 40-80 Asker C hardness, ormore particularly 50-70 Asker C hardness. In addition, selectivepress-forming (through variation in the shape of the preform and/orvariation in the pressure applied in different regions duringpress-forming) can be used to produce any appropriate smoothly varyingand/or stepped variation in hardness and density throughout the midsolecomponent 300.

In one embodiment the midsole component 300 can mate with one or moreadditional midsole components to form a full midsole for a shoe. Anexample sole for a shoe 400 including a two component midsole 405 isshown in FIGS. 7A through 8. In this embodiment, the midsole component300 forms a lower portion of the midsole 405 within the heel 410 andmidfoot 415 of the shoe 400. An upper midsole component 425 mates to theupper surface 430 of the central base region 310 of the midsolecomponent 300, with the upper midsole component 425 extending into theforefoot 420 of the shoe 400 to form a forefoot portion of the midsole405. The upper surface of the midsole 435 is formed by the upper surfaceof the upper midsole component 440 and, in the perimeter regions of themedial and lateral midfoot/heel region, the upper surface of the medialside region 315 and the lateral side region 335. The upper midsolecomponent 425 may, in certain embodiments, be formed from a softer orless dense material (e.g., a softer EVA foam) than the midsole component300, and can therefore provide a softer, more cushioned surface for thefoot of the wearer to rest on, while the perimeter regions of themidsole component 300 can provide additional support for the foot on thelateral and/or medial sides.

In one embodiment the midsole component 300 and the upper midsolecomponent 425 is bonded together by a cementing system (e.g., anadhesive bonding agent) such as, but not limited to, a urethane,silicone, or EVA-based cementing system, or the like. In alternativeembodiments the midsole component 300 and the upper midsole component425 may be connected through any appropriate chemical and/or mechanicalmechanisms, or may be co-molded into a unitary midsole 400 in a moldingprocess. In a further alternative embodiment the midsole component 300and the upper midsole component 425 may not be bonded together, but mayrather conformingly mate together without the need for a separatebonding material, with, in one embodiment, the upper midsole component425 being potentially removable from the midsole component 300.

In one embodiment one or more outsole elements 450 (e.g., a groundcontacting rubber) can be bonded or otherwise affixed to a lower surfaceof the midsole 405 to form a ground contacting surface for the shoe 400.In another embodiment the midsole component 300 and the upper midsolecomponent 425 can be formed from ground-contact EVA, thereby allowingthe bottom surface of the midsole 405 to function as a ground contactingsurface without the need for additional outsole elements. In oneembodiment the upper surface of the midsole 435 can function as a footcontacting surface which directly contacts the foot of a wearer. In analternative embodiment one or more additional elements, e.g., an insoleand/or a strobel board, may be located between the upper surface of themidsole 435 and the foot of a wearer.

In an alternative embodiment the midsole 405 may be formed as a singleunitary component having a variable density distribution configuredtherein. In a further alternative embodiment the midsole may includethree or more separate elements with, for example, separate variabledensity components within the heel, midfoot and/or forefoot sections(with a cushioning element joining these components) to provide separatecontrolled support and cushioning within different regions of the sole.In a further alternative embodiment the midsole 405 may include separatevariable-density components in the medial and lateral sides, or havingvariable density components only in one of a medial side, lateral side,or heel of the sole.

In one embodiment the methods described herein may be utilized toproduce a variable density insole for an article of footwear, where theinsole can be configured with any appropriate density distribution toprovide appropriate levels of support and cushioning to differentregions of a foot. Alternatively, the methods described herein may beutilized to produce a variable density insert for locating within aportion of an interior of a shoe (e.g., in a heel, midfoot, and/orforefoot region) to provide a removable insert for providing targetedsupport and/or cushioning for a wearer. The insert may, in variousembodiments, be located within a midsole of the shoe, or be locatedabove the midsole of a shoe as an insole component or as a separateelement to be placed above the insole.

In one embodiment a variable density midsole component may be locatedwithin a forefoot of a shoe. This may be advantageous, for example, inproducing wedged elements in a lateral forefoot region which can bebeneficial in supporting cutting-type movements of an athlete. Invarious embodiments any lateral and/or medial wedge elements may beformed using the methods described herein.

The shoe 400 includes an upper 460 having a foot opening 465 and afastening mechanism including laces 470. In alternative embodiments theshoe 400 may have any appropriate form of closing mechanism and, or beof any appropriate form (e.g., a boot, an athletic shoe, a work shoe, aflip-flop, a flat, a high heeled shoe, etc.).

In one embodiment a sole element for a shoe, and for example an athleticshoe such as a training shoe or cleated shoe, can include a variabledensity/hardness component formed as a perimeter portion extendingthrough a plurality of regions of the shoe (e.g., within a medialmidfoot, heel, and lateral midfoot region). In one embodiment thevariable-density perimeter element(s) can extend into a forefoot regionof the sole and may, in one embodiment, form a closed perimeterextending around the entire perimeter of the sole. In one embodiment thevariable-density/hardness perimeter element can be formed with a baseregion extending in a bottom region of the sole, with a cushioningelement (e.g., an upper midsole component) placed above the base regionand being surrounded by the perimeter region. In another embodiment thevariable-density/hardness perimeter element(s) does not have a baseregion, with an entire central region of the sole formed by one or moreseparate cushioning element/upper midsole component. The cushioningelement can extend to a same height as the perimeter region or extendover a top surface of the perimeter region. In cleated embodiment, thecleats may extend from a bottom of the variable-density/hardnessperimeter element, from the bottom of the base region, and/or from thebottom of the cushioning element/upper midsole component. Alternatively,one or more plates with one or more cleats attached thereto (and/orintegrally formed therewith) can be attached to a bottom surface of thevariable-density/hardness perimeter element, base region, and/orcushioning element/upper midsole component.

It should be understood that alternative embodiments, and/or materialsused in the construction of embodiments, or alternative embodiments, areapplicable to all other embodiments described herein.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The foregoingembodiments, therefore, are to be considered in all respectsillustrative rather than limiting the invention described herein. Scopeof the invention is thus indicated by the appended claims, rather thanby the foregoing description, and all changes that come within themeaning and range of equivalency of the claims are intended to beembraced therein.

What is claimed is:
 1. A method of manufacturing a sole element for anarticle of footwear, the method comprising the steps of: forming a soleelement preform; inserting the sole element preform into a press moldcavity; and press-forming the sole element preform within the press moldcavity to form a unitary finished sole element comprising: a firstperimeter region comprising a first maximum density; a second perimeterregion comprising a second maximum density; a third perimeter regioncomprising a third maximum density; and a central region comprising afourth maximum density extending between at least a portion of the firstperimeter region, second perimeter region, and third perimeter region.2. The method of claim 1, wherein the first perimeter region comprisesat least a portion of a lateral side region of the sole element, thesecond perimeter region comprises at least a portion of a medial sideregion of the sole element, and the third perimeter region comprises atleast a portion of a lateral heel region of the sole element, whereinthe third maximum density is less than at least one of the first maximumdensity or the second maximum density.
 3. The method of claim 1, whereinthe sole element preform comprises a polymeric material.
 4. The methodof claim 3, wherein forming the sole element preform comprises foamingunfoamed polymeric material in a first mold cavity.
 5. The method ofclaim 4, wherein the press mold cavity has a volume smaller than that ofthe first mold cavity, and wherein inserting the sole element preforminto the press mold comprises over-stuffing the sole element preforminto the press form cavity.
 6. The method of claim 4, wherein theunfoamed polymer material further comprises at least one coloringmaterial, and wherein upon foaming the unfoamed polymeric material thecoloring material is unevenly distributed throughout the sole elementpreform.
 7. The method of claim 6, wherein upon press-forming the soleelement preform to form the finished sole element the unevenlydistributed coloring material provides a visual indicationrepresentative of a differentiation in density in different regions ofthe finished sole element.
 8. The method of claim 1, wherein: the firstmaximum density is less than the second maximum density: the thirdmaximum density is less than both the first maximum density and thesecond maximum density; and the fourth maximum density is less than atleast one of the first maximum density and the second maximum density.9. The method of claim 1, wherein at least one of the first perimeterregion, second perimeter region, and third perimeter region comprises adensity that varies in at least one direction.
 10. The method of claim1, wherein the finished sole element is adapted to form at least a heelportion of a midsole of an article of footwear.
 11. A sole element foran article of footwear comprising: a first perimeter region comprising afirst maximum density; a second perimeter region comprising a secondmaximum density; a third perimeter region comprising a third maximumdensity; and a central region comprising a fourth maximum density andextending between at least a portion of the first perimeter region,second perimeter region, and third perimeter region, and wherein each ofthe first perimeter region, second perimeter region, third perimeterregion, and central region comprise a unitary construction.
 12. The soleelement of claim 11, wherein the first perimeter region comprises atleast a portion of a lateral side region of the sole element, the secondperimeter region comprises at least a portion of a medial side region ofthe sole element, and the third perimeter region comprises at least aportion of a lateral heel region of the sole element, and wherein thethird maximum density is less than at least one of the first maximumdensity or the second maximum density.
 13. The sole element of claim 11,wherein the unitary construction comprises a polymeric material.
 14. Thesole element of claim 11, wherein the polymeric material comprises atleast one coloring material providing a visual indication representativeof a differentiation in density in different regions of the soleelement.
 15. The sole element of claim 11, wherein: the first maximumdensity is less than the second maximum density: the third maximumdensity is less than both the first maximum density and the secondmaximum density; and the fourth maximum density is less than at leastone of the first maximum density and the second maximum density.
 16. Thesole element of claim 11, wherein at least one of the first perimeterregion, second perimeter region, and third perimeter region comprises adensity that varies in at least one direction.
 17. The sole element ofclaim 11, wherein the sole element is adapted to form at least a heelportion of a midsole of an article of footwear.
 18. A sole element foran article of footwear comprising: a first sole component comprising afirst material, the first sole component comprising an upper surface anda lower surface, the upper surface of the first sole element forming atleast a first portion of an upper surface of the sole element; and asecond sole component comprising a second material, the second solecomponent comprising an upper surface and a lower surface, and at leasta first portion of the upper surface of the second component adapted tomate to at least a portion of the lower surface of the first solecomponent, wherein the second component comprises a first regioncomprising a first maximum density, and a second region comprising asecond maximum density different from the first maximum density.
 19. Thesole element of claim 18, wherein: the first region of the second solecomponent comprises at least one lateral extension extending upwardsaround at least a portion of a lateral side of the first sole componentand having an upper surface adapted to extend to a same height as theupper surface of the first sole element to form a second portion of anupper surface of the sole element; and the second region of the secondsole component comprises at least one medial extension extending upwardsaround at least a portion of medial side of the first sole component andhaving an upper surface adapted to extend to a same height as the uppersurface of the first sole element to form a second portion of an uppersurface of the sole element.
 20. The sole element of claim 19, whereinthe second sole component further comprises a heel region comprising athird maximum density different from at least one of the first maximumdensity and the second maximum density.